Integrated transcriptomic and metabolomic analysis shows that disturbances in metabolism of tumor cells contribute to poor survival of RCC patients

Purpose: Cellular metabolism of renal cell carcinoma (RCC) tumors is disturbed. The clinical significance of these alterations is weakly understood. We aimed to find if changes in metabolic pathways contribute to survival of RCC patients. Material and methods: 35 RCC tumors and matched controls were used for metabolite profiling using gas chromatography -mass spectrometry and transcriptomic analysis with qPCR-arrays targeting the expression of 93 metabolic genes. The clinical significance of obtained data was validated on independent cohort of 468 RCC patients with median follow-up of 43.22 months. Results: The levels of 31 metabolites were statistically significantly changed in RCC tumors compared with controls. The top altered metabolites included beta-alanine (+4.2-fold), glucose (+3.4-fold), succinate (-11.0fold), myo-inositol (-4.6-fold), adenine (-42-fold), uracil (-3.7-fold), and hypoxanthine (-3.0-fold). These disturbances were associated with altered expression of 53 metabolic genes. ROC curve analysis revealed that the top metabolites discriminating between tumor and control samples included succinate (AUC = 0.91), adenine (AUC = 0.89), myo-inositol (AUC = 0.87), hypoxanthine (AUC = 0.85), urea (AUC = 0.85), and beta-alanine (AUC = 0.85). Poor survival of RCC patients correlated (p < 0.0001) with altered expression of genes involved in metabolism of succinate (HR = 2.7), purines (HR = 2.4), glucose (HR = 2.4), beta-alanine (HR = 2.5), and myo-inositol (HR = 1.9). Conclusions: We found that changes in metabolism of succinate, beta-alanine, purines, glucose and myo-inositol correlate with poor survival of RCC patients. (C) 2016 Elsevier B.V. All rights reserved.